Fluid oscillator



Jan. 9, 1962 R. w. WARREN 3,016,066

FLUID OSCILLATOR Filed Jan. 22, 1960 INVENTOR, R 5.5m an cf WWEIT eh.

United States Patent 3,016,066 FLUID OSCILLATOR Raymond W. Warren, 2515 Seneca Ave., McLean, Va.

Filed Jan. 22, 1960, Ser. No. 4,162

Claims. (Cl. 137-62414) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a fluid-operated system which utilizes the flow of a fluid so that the system performs functions which are analogous to some functions now being performed by electronic components and systems. It is also desirable that systems other than electronic perform the same or analogous functions without requiring a source of electrical energy or delicate electronic components. While known mechanical systems will perform somewhat analogous to functions performed by electronic systems, the former systems require a largenumber of moving parts. Failure in any part usually results in improper operation of the system.

An object of the invention is to provide a fluid-operated system which performs some functions which are analogous to functions performed by existing electronic systems.

Another object of the invention is to utilize the flow of a stream of fluid under pressure so that the fluid acts in a manner similar to manner in which electrons act in electronic systems.

A further object of the invention is toprovide a fluidoperated system in accordance with the above objects, which requires no moving parts.

Still another object is to utilize the principle of boundary layer control to effect a definite multiple switching action of the fluid stream.

Specifically, the object of this invention, in accordance with the aforementioned objects, is a fluid oscillator which utilizes a jet of air which is made to oscillate back and forth between two passages in such a manner that it can be used for timing and other purposes where an alternating air stream is desired.

According to this invention, the energy of a fluid stream is utilized in a unique system which has no moving parts. The system utilizes the principle of boundary layer control so that fluid under pressure performs a definite oscillating action between apertures.

The specific nature of the invention, as well as other objects, uses and advantages thereof, will clearly appear from the following description and the accompanying drawing, in which:

FIG. 1 is a plan view of the fluid-operated oscillator in accordance with the principles of this invention.

FIG. 2 is a side view of the oscillator shown in FIG. 1 with means for supplying fluid to the oscillator.

FIG. 3 is a fragmentary plan view illustrating the setback.

In FIG. 1 there is shown an embodiment of the fluidoscillator wherein 17 indicates a housing formed by three flat plates, 1, 2, and 3 (FIG. 2). Plate 3 is positioned between plates 1 and 2 and is sealed between these two plates by machine screw 5. These plates may be composed of any metallic, plastic, ceramic or other suitable material. For the purpose of illustration the plates are shown composed of clear plastic material.

The configuration cut from plate 3 provides a chamber 6, feedback passage 7, fluid supply nozzle 8, and apertures 9 and 10 and their orifices 9a and 10a. The feedback passa e is provided with oppositely disposed orifices 7a and 7b in communication with chamber 6 and substantially at right angles to orifice 8a of the fluid supply nozzle 8. The term orifice, as used herein, includes orifices one side of the divider 11 than the other.

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ventional shape. The input end 8b of nozzle 8 communicates with threaded bore 15 formed in plate 2.

Orifices 9a and 10a form openings for apertures 9 and 10 respectively and are normally symmetrically spaced relative to nozzle 8. Divider 11 is formed to, if so desired, provide symmetry between orifices 9a and 10a. The end 11a of divider 11 defines the entrance to orifices 9a and 10a. Both orifices 9a and 1011 have identical cross-sectional areas in the embodiment illustrated in the drawings. A pair of oppositely diverging walls 12 and 12a forming chamber 6 join the outer walls of orifices 9a and 10a, respectively, and communicate with apertures 9 and 10 to form a smooth continuous surface three between.

Bores 13, 14 and 15 formed in plate 2 are threaded to receive tubes 13a, 14a and 15a respectively. The end of the tube 15a extending from plate 2 is attached to a source of fluid under pressure indicatedby reference numeral 16.

The output of fluid oscillator 17 may be taken from tubes 13a and as particularly illustrated in FIG. 2. When powernozzle 8 initially issues fluid, the-resulting power jet entrains particles adjacent to its flow and tends to evacuate the chamber through which it flows. As the power jet issues from orifice 8a, it strikes the divider 11.

The stream is slightly turbulent so more of it passes on Since there is a chamber wall such as wall 12 or 12a near one side of the stream the wall will impede the flow of particles to the stream. Since the turbulence causes more fluid to flow on one side of the divider than the other, and since the divider is symmetrical, the stream is closer to one wall than the other. Thus as regards that one wall, the stream is more effective in evacuating the area between the stream and that wall. Thus the space between the stream and wall tends to become evacuated, the pressure of particles on the opposite side of the stream towards the wall thereby increasing. As the stream moves further towards that wall the evacuation process becomes even more eflicient. This action which produces boundary lock-0n is regenerative and the stream is finally forced against the wall, so that all of the stream will flow from either aperture 9 or 19 depending upon which wall the stream locked onto. Assume for purposes of illustration that because of stream turbulence the power jet is closer to wall 12 than wall 12a, and therefore is more eflicient in evacuating fluid from the region between wall 12 and the stream than from the region between the stream and wall 12a. This will cause the stream to lock on wall 12 and flow out of aperture 9.

As the power jet flows out aperture 9 a counter flow is induced in aperture 10. Initially fluid will be evacuated from both orifices 7a and 7b and flow out feedback passage 7. However, since more fluid is flowing across orifice 7a, the fluid is evacuated more eficiently from that orifice so the flow at orifice 7b will reverse and a pressure wave will proceed from orifice 7a to orifice 7b at the speed of sound in the local medium.

Similarly, a rarefraction wave will travel from orifice 7a to orifice 7b reducing the differential pressure which tends to force the power jet towards orifice 7a. The rarefraction wave arrives at orifice 7b at the same time the pressure wave arrives at orifice 7a. The combined effect of a reduced pressure at 7b and an increased pressure at 7a occurring in phase causes the power jet issuing from nozzle 8 to shift from aperture 9 to aperture 10. Then there is a sudden reversal of flow. Where the fluid flow was flowing into aperture 10 it is now flowing from that aperture, and where the fluid was flowing from aperture 9 is is now flowing into that aperture.

Similarly, where the flow was flowing from orifice 7a of feedback passage 7, it is now flowing into that orifice.

'This fluid creates a pressure wave which travels at the speed of sound in the medium through the feedback pas sage 7 to orifice 7b where it issues as a jet to cause the power jet to shift to aperture 9 again.

Fluids which can be employed in my oscillator include air, or other gases, water, or other liquids. Gas, with or without solid particles has been found to work satisfactorily.

Thus it can be seen that the power jet oscillates between orifice 9a and orifice 10a alternately producing pulses in the apertures 9 and 10. The frequency of the oscillation depends primarily on the length of feedback passage, but also on the relative size the orifices at the ends of the feedback passage with respect to the power jet flow and setback feature of the device. By increasing the area of the orifices, the force which deflects the stream issuing from orifice 8a increases because force equals pressure times area. The increased force deflects the stream into the opposite aperture in less time thereby increasing the frequency. Consequently by increasing the orifice area the rate of oscillation increases. The referred to setback is the distance wall 12 and 12a are set back relative to orifice 8a as illustrated in FIG. 3 of the drawmgs.

It will be apparent that the embodiment shown is only exemplary and that various modifications can be made in construction and arrangement within the scopeof the invention as defined in the appended claims.

I claim:

1. A fluid oscillator comprising: a pair of opposed surfaces capable of supporting fluid flow thereupon, means issuing a fluid stream between said surfaces, said surfaces diverging from said stream so issued such thatsaid stream can lock on to either surface, nozzles for issuing fluid between said stream and said surfaces so as to deflect said stream between said surfaces, and regenerative means connecting said nozzles together, said regenerative means causing said nozzles to issue alternating fluid jets between said stream and said surfaces.

2. The invention as claimed in claim 1, wherein said regenerative means comprises a feedback passage.

3. The invention as claimed in claim 2, wherein the frequency of oscillation of the fluid stream is determined No references cited. 

